1. Developmental Biology
  2. Neuroscience
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The Makorin lep-2 and the lncRNA lep-5 regulate lin-28 to schedule sexual maturation of the C. elegans nervous system

  1. Hannah Lawson
  2. Edward Vuong
  3. Renee M Miller
  4. Karin Kiontke
  5. David HA Fitch
  6. Douglas S Portman  Is a corresponding author
  1. University of Rochester, United States
  2. New York University, United States
Research Article
Cite this article as: eLife 2019;8:e43660 doi: 10.7554/eLife.43660
6 figures, 1 table and 1 additional file

Figures

Five classes of neurons undergo male-specific functional maturation during the larval-to-adult transition.

(A–E) Rows show expression of reporter genes for srj-54, odr-10, mab-3, daf-7, and pkd-2, respectively. At the left, the name of each marker, a brief description of its gene product, and the cell type whose maturation it marks are indicated. For all rows, representative epifluorescence (above; dashed line indicates outline of body) and DIC (below) images are shown for the indicated sex and stage. The graph at the right of each row shows expression levels in L3, L4, and adult males. Asterisks indicate the statistical significance of comparisons between L3 and L4 and between L4 and adult. Numbers above each bar indicate numbers of animals scored.

https://doi.org/10.7554/eLife.43660.003
Figure 2 with 1 supplement
Heterochronic genes regulate the sexual maturation of multiple C. elegans neurons.

(A) A subset of the heterochronic pathway, indicating genes and regulatory events important for the timing of the juvenile-to-adult transition in hypodermal tissues. (B) The temporal dynamics of lep-2, lep-5, lin-28, and let-7 expression during larval development. (C–G) Expression of markers for the sexual maturation of five neuron classes in wild-type and heterochronic mutants. For each marker, expression is shown in the males of the indicated stage (L3, L4, and Adult) and genotype. ‘–” indicates that a null allele was used, while ‘lf’ and ‘gf’ indicate hypomorphic and hypermorphic alleles, respectively. For lin-28(–) and lin-41(lf), only L3 and L4 males were scored. All strains were grown at 20°C except for let-7(lf) and lin-41(bx42) and their paired wild-type controls, which were grown at 25°C. Asterisks indicate the statistical significance of comparisons to paired wild-type controls of the same stage. Paired wild-type control data was pooled to create the WT graph at the left of each row. Numbers above each bar indicate numbers of animals scored. Graphs are shaded to indicate temporal phenotypes as shown in the legend.

https://doi.org/10.7554/eLife.43660.005
Figure 2—figure supplement 1
Structural features of the lep-5 lncRNA required for its function in the nervous system.

(A) A predicted model for lep-5 secondary structure; see Kiontke et al., 2019 for details. Colored shading indicates regions disrupted by the mutants tested. (B) Expression of Psrj-54::YFP in adult males of the indicated genotype. Numbers above each bar indicate numbers of animals scored. (C) The fs21 allele mutates six nucleotides (shown in red) important for the predicted zipper ‘a’ region. The fs21 fs25 allele mutates an additional seven positions ~ 325 nt in the 3´ direction in a manner predicted to allow zipper ‘a’ to re-form, even in the presence of significant changes in its primary sequence (Kiontke et al., 2019).

https://doi.org/10.7554/eLife.43660.006
Figure 3 with 1 supplement
The heterochronic pathway is a cell-autonomous, distributed timer of sexual maturation.

(A) Models for non-autonomous and autonomous functions of the heterochronic pathway, as described in the text. (B) Expression of LIN-28::GFP and the pan-neural nuclear marker Prab-3::nRFP. Strong GFP expression is detected throughout the nervous system of L1 animals; this decreases during L2 and is virtually undetectable in L3. (C) Plep-5::GFP expression in L1, L2, and L3 animals. GFP is essentially undetectable in L1 but is seen in many head neurons in L2 and L3. (D) Plep-2::GFP::LEP-2 expression in L3, L4, and Adult males. Broad GFP expression is seen in the nervous system at all stages examined. (E–H) Cell-type specific rescue. Numbers above each bar indicate numbers of animals scored. Asterisks indicate the significance of the comparison between transgenic animals and non-transgenic control siblings. (E) Expression of Psrj-54::YFP in wild-type, lep-2 (non-transgenic siblings), and lep-2; AIM::lep-2 males of the indicated stage. (F) Expression of ODR-10::GFP in wild-type, lep-2 (non-transgenic siblings), and lep-2; AIM::lep-2 males of the indicated stage. (G) Expression of Psrj-54::YFP in wild-type, lin-28 (non-transgenic siblings), and lin-28; AIM::lin-28 males of the indicated stage. (H) Expression of ODR-10::GFP in wild-type, lep-2 (non-transgenic siblings), and lep-2; AWA::lep-2 adult males.

https://doi.org/10.7554/eLife.43660.009
Figure 3—figure supplement 1
lin-4 is necessary for proper lep-5::GFP expression in the nervous system.

Images show expression of the Plep-5::GFP reporter (left), the pan-neural nuclear marker Prab-3::nlsRFP (right) and the merged image (center) in the indicated stages of (A) wild-type and (B) lin-4(e912) mutants. Dashed lines indicate the body outline. The images in (A) are of the same individual as in Figure 3C, shown here in wider-view versions.

https://doi.org/10.7554/eLife.43660.010
Figure 4 with 1 supplement
Regulatory relationships and conservation of heterochronic function.

(A) LIN-28::GFP expression persists into L3 in lep-2 mutants (right), unlike wild-type (left). The images on the left are the same as those in Figure 3C, but the GFP signal intensity is doubled to highlight the difference in expression in L3. Images for wild-type and mutant were taken with identical settings and images were processed identically. (B–D) Psrj-54::YFP expression in the indicated single and double mutant adult males. Numbers above each bar indicate numbers of animals scored. (E–G) MKRN3 overexpression in the nervous system. Non-transgenic siblings were used as WT controls. Numbers above each bar indicate numbers of animals scored. Asterisks indicate significance of the comparison of transgenic animals to control animals of the same stage. (E) Psrj-54::YFP expression in animals of the indicated genotype and stage. (F) ODR-10::GFP expression in animals of the indicated genotype and stage. (G) Ppkd-2::GFP expression in animals of the indicated genotype and stage.

https://doi.org/10.7554/eLife.43660.012
Figure 4—figure supplement 1
Genetic control of male sexual differentiation and behavior.

(A) MKRN3 overexpression in the nervous system of lep-2 mutants. Bars indicate distributions of the intensity of Psrj-54::YFP expression. Non-transgenic siblings were used as WT controls. Numbers above each bar indicate numbers of animals scored. (B–D) Expression of Psrj-54::YFP (B) and ODR-10::GFP (C,D) in mab-3 (B–C) and lin-29a (D) mutants. Numbers indicate number of animals scored. Asterisks indicate statistical comparisons between WT and mutant animals. (E) Attraction to ascaroside pheromones using a quadrant-style assay. Each point represents the chemotaxis index calculated from one assay (ten animals). Asterisks indicate the significance of the indicated comparisons.

https://doi.org/10.7554/eLife.43660.013
Adult-specific male behavior requires the function of the heterochronic pathway.

(A) Food-leaving behavior. The maximum distance that a single animal had travelled from a small food spot was determined at 3, 6, and 24 hr after the beginning of the assay. Numbers indicate number of animals assayed. Asterisks indicate significance of comparisons to wild-type adults. (B) Attraction to a blend of ascaroside pheromones (ascr#2/#3/#8) using a quadrant-style assay. Each point represents the chemotaxis index calculated from one assay (ten animals). (C, D) Contact-response (Rsp) and Vulva-location (Lov) behavior. Numbers indicate number of animals tested. pkd-2 mutant males, known to be defective in both behaviors (Barr et al., 2001), are used as controls.

https://doi.org/10.7554/eLife.43660.016
The heterochronic and sex-determination pathways intersect to control adult-specific male gene expression and behavior.

Genes are color-coded to indicate function as indicated. Grey arrows from MKRN3 represent hypothetical interactions that could explain the ability of MKRN3 to inhibit C. elegans sexual differentiation. See text for details.

https://doi.org/10.7554/eLife.43660.018

Tables

Key resources table
Reagent type
(species) or
resource
DesignationSource or referenceIdentifiersAdditional information
Gene
(C. elegans)
him-5NAWormBase
ID: WBGene00001864
Gene
(C. elegans)
lep-2NAWormBase
ID: WBGene00002278
Gene
(C. elegans)
lep-5NAWormBase
ID: WBGene00010424
Gene
(C. elegans)
let-7NAWormBase
ID: WBGene00002285
Gene
(C. elegans)
lin-28NAWormBase
ID: WBGene00003014
Gene
(C. elegans)
lin-29NAWormBase
ID: WBGene00003015
Gene
(C. elegans)
lin-4NAWormBase
ID: WBGene00002993
Gene
(C. elegans)
lin-41NAWormBase
ID: WBGene00003026
Gene
(C. elegans)
mab-3NAWormBase
ID: WBGene00003100
Gene
(C. elegans)
pha-1NAWormBase
ID: WBGene00004010
Gene
(C. elegans)
unc-31NAWormBase
ID: WBGene00006767
Gene
(human)
MKRN3NAHGNC:7114
Strain, strain
background
(C. elegans)
otIs355[rab-3p(prom1)::
2xNLS::TagRFP] IV;
him-5(e1490) V;
nyEx62[Plep-5::GFP + pRF4]
this paperDF305otIs355: OH10689;
e1490: CB4088;
nyEx62 see below
Strain, strain
background
(C. elegans)
lin-4(e912) II;
otIs355[rab-3p(prom1)::
2xNLS::TagRFP] IV
; him-5(e1490) V;
nyEx62[Plep-5::GFP + pRF4]
this paperDF306e912: CB2627;
otIs355: OH10689;
e1490: CB4088;
nyEx62 see below
Strain, strain
background
(C. elegans)
pkd-2(sy606) IV;
him-5(e1490) V
Caenorhabditis Genetics CenterPT8RRID:WB-STRAIN:PT8
Strain, strain
background
(C. elegans)
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V
Lee and Portman, 2007UR219
Strain, strain
background
(C. elegans)
him-5(e1490) V;
kyIs53[Podr-10::odr-10::GFP] X
Ryan et al., 2014UR460
Strain, strain
background
(C. elegans)
unc-31(e169) IV;
him-5(e1490) V
PMID: 22023935UR624
Strain, strain
background
(C. elegans)
mab-3(e1240) II;
him-5(e1490) V;
kyIs53[ODR-10::GFP] X
this paperUR626e1240: UR278;
e1490: UR926;
kyIs53: CX3344
Strain, strain
background
(C. elegans)
pha-1(e2123) III;
him-5(e1490) V;
fsEx295[ODR-10::GFP
fosmid + pBx1]
Ryan et al., 2014UR773
Strain, strain
background
(C. elegans)
him-5(e1490) V;
lin-41(bx42) X;
fsEx295[ODR-10::GFP
fosmid + pBx1]
this paperUR786e1490: UR926;
bx42: EM106;
fsEx295: UR773
Strain, strain
background
(C. elegans)
lin-41(bx42) I;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V
this paperUR869bx42: EM106;
fsIs5: UR218;
e1490: UR926
Strain, strain
background
(C. elegans)
lin-41(ma104) I;
myIs4[Ppkd-2::pkd-2::
GFP + cc::GFP] him-5
(e1490) V
this paperUR871ma104: CT8;
myIs4: UR1258;
e1490: UR1258
Strain, strain
background
(C. elegans)
lin-28(n719) I;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V
this paperUR872n719: MT1524;
fsIs5: UR218;
e1490: UR218
Strain, strain
background
(C. elegans)
lin-28(n719) I;
myIs4[Ppkd-2::pkd-2::
GFP + cc::GFP] him-5
(e1490) V
this paperUR873n719: MT1524;
myIs4: UR1258;
e1490: UR1258
Strain, strain
background
(C. elegans)
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V; lep-5(fs8) X
this paperUR874fsIs5: UR218;
e1490: UR218;
fs8: UR290
Strain, strain
background
(C. elegans)
myIs4[Ppkd-2::pkd-2::GFP
 + cc::GFP] him-5(e1490) V;
lep-5(fs8) X
this paperUR876myIs4: UR1258;
e1490: UR1258;
fs8: UR290
Strain, strain
background
(C. elegans)
myIs4[Ppkd-2::pkd-2::GFP
 + cc::GFP] him-5(e1490)
V; let-7(n2853) X
this paperUR878myIs4: UR1258;
e1490: UR1258;
n2853: MT7626
Strain, strain
background
(C. elegans)
him-5(e1490) Vthis paperUR926e1490: CB4088
Strain, strain
background
(C. elegans)
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V; lep-5(fs20) X
this paperUR1248fsIs5: UR218;
e1490: UR218;
fs20: UR1142
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V
this paperUR1249ok900: RB986;
fsIs5: UR218;
e1490: UR218
Strain, strain
background
(C. elegans)
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V; let-7(n2853) X
this paperUR1250fsIs5: UR218;
e1490: UR218;
n2853: MT7626
Strain, strain
background
(C. elegans)
pha-1(e2123) III;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx295[ODR-10::
GFP fosmid + pBx1]
this paperUR1251e2123: GE24;
e1490: UR926;
fsEx295: UR773
Strain, strain
background
(C. elegans)
pha-1(e2123) III;
lep-2(ok900) IV;
him-5(e1490) V;
fsEx295[ODR-10::GFP
fosmid + pBx1]
this paperUR1252e2123: GE24;
ok900: RB986;
e1490: UR926;
fsEx295: UR773
Strain, strain
background
(C. elegans)
lin-28(n719) I;
pha-1(e2123) III;
him-5(e1490) V;
fsEx295[ODR-10::GFP
fosmid + pBx1]
this paperUR1253n719: MT1524;
e2123: GE24;
e1490: UR926;
fsEx295: UR773
Strain, strain
background
(C. elegans)
him-5(e1490) V;
let-7(n2853) X;
fsEx295[ODR-10::GFP
fosmid + pBx1]
this paperUR1254e1490: UR926; n2853:
MT7626; fsEx295: UR773
Strain, strain
background
(C. elegans)
pha-1(e2123) III;
him-5(e1490) V;
let-41(ma104) X;
fsEx295[ODR-10::GFP
fosmid + pBx1]
this paperUR1255e2123: GE24;
e1490: UR926;
ma104: CT8; fsEx294:
UR773
Strain, strain
background
(C. elegans)
lin-29a(xe38) II;
him-5(e1490) V;
kyIs53[Podr-10::odr-
10::GFP] X
this paperUR1256xe38: HW1693;
e1490: UR926;
kyIs53: CX3344
Strain, strain
background
(C. elegans)
lin-29a(xe40) II;
him-5(e1490) V;
kyIs53[Podr-10::odr
-10::GFP] X
this paperUR1257xe40: HW1695;
e1490: UR926;
kyIs53: CX3344
Strain, strain
background
(C. elegans)
myIs4[Ppkd-2::pkd-2::
GFP + cc::GFP] him-5
(e1490) V
this paperUR1258myIs4: PT621;
e1490: PT621
Strain, strain
background
(C. elegans)
myIs4[Ppkd-2::pkd-2::
GFP + cc::GFP]
him-5(e1490) V;
lep-5(ny28) X
this paperUR1259myIs4: PT621;
e1490: PT621;
ny28: UR1022
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
myIs4[Ppkd-2::pkd-2::
GFP + cc::GFP] him-5
(e1490) V
this paperUR1260ok900: RB986;
myIs4: UR1258;
e1490: UR1258
Strain, strain
background
(C. elegans)
lin-41(bx42) I;
myIs4[Ppkd-2::pkd-2::
GFP + cc::GFP] him-5
(e1490) V
this paperUR1261bx42: EM106;
myIs4: UR1258;
e1490: UR1258
Strain, strain
background
(C. elegans)
him-5(e1490) V;
lep-5(ny28) X;
fsEx527[1.5 kb
MAB-3::GFP (pDZ162) + 
cc::GFP]
this paperUR1262e1490: UR926;
ny28: UR1022;
fsEx527: UR1131
 strain, strain
background
(C. elegans)
lep-2(ok900) IV;
him-5(e1490) V;
fsEx527[1.5 kb
MAB-3::GFP
(pDZ162) + cc::GFP]
this paperUR1263ok900: RB986;
e1490: UR926;
fsEx527: UR1131
Strain, strain
background
(C. elegans)
lin-28(n719) I;
him-5(e1490) V;
fsEx527[1.5 kb
MAB-3::GFP (pDZ162)
 + cc::GFP]
this paperUR1264n719: MT1524;
e1490: UR926;
fsEx527: UR1131
Strain, strain
background
(C. elegans)
him-5(e1490) V;
ksIs2[Pdaf-7::GFP + 
rol-6(su1006)]
this paperUR1265e1490: UR926;
ksIs2: FK181
Strain, strain
background
(C. elegans)
him-5(e1490) V;
lep-5(ny28) X;
ksIs2[Pdaf-7::
GFP + rol-6(su1006)]
this paperUR1266e1490: UR926;
ny28: UR1022;
ksIs2: FK181
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
him-5(e1490) V;
ksIs2[Pdaf-7::GFP + rol-6(su1006)]
this paperUR1267ok900: RB986;
e1490: UR926;
ksIs2: FK181
Strain, strain
background
(C. elegans)
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx559[Prab-3::MKRN3::SL2::
mCherry::unc-54 3' UTR 
+ Pmyo-3::mCherry Line 1]
this paperUR1268fsIs5: UR218;
e1490: UR926;
fsEx559: see below
Strain, strain
background
(C. elegans)
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx560[Prab-3::MKRN3::SL2::
mCherry::unc-54 3' UTR 
+ Pmyo-3::mCherry Line 2]
this paperUR1269fsIs5: UR218;
e1490: UR926;
fsEx560: see below
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx561[Peat-4prom11::lep-
2::Sl2::mCherry::unc-54 3'
UTR + Pmyo-3::mCherry Line 1]
this paperUR1270ok900: RB986;
fsIs5: UR218;
e1490: UR218;
fsEx561: see below
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx562[Peat-4prom11::lep-
2::Sl2::mCherry::unc-54 3'
UTR + Pmyo-3::mCherry Line 2]
this paperUR1271ok900: RB986;
fsIs5: UR218;
e1490: UR218;
fsEx562: see below
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V; fsEx563[Peat-
4prom11::lep-2::Sl2::mCherry::unc-54
3' UTR + Pmyo-3::mCherry Line 3]
this paperUR1272ok900: RB986;
fsIs5: UR218;
e1490: UR218;
fsEx563: see below
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx564[Prab-3::MKRN3::SL2::
mCherry::unc-54 3'
UTR + Pmyo-3::mCherry Line 1]
this paperUR1273ok900: RB986;
fsIs5: UR218; e1490:
UR218; fsEx564:
see below
Strain, strain
background
(C. elegans)
lep-2(ok900) IV;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx565[Prab-3::MKRN3::SL2::
mCherry::unc-54 3' UTR + 
Pmyo-3::mCherry Line 2]
this paperUR1274ok900: RB986;
fsIs5: UR218;
e1490: UR218;
fsEx565: see below
Strain, strain
background
(C. elegans)
lin-28(n719) I;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx566[Peat-4prom11::lin-
28::Sl2::mCherry::unc-54 3'
UTR + Pmyo-3::mCherry Line 1]
this paperUR1275n719: MT1524;
fsIs5: UR218;
e1490: UR218;
fsEx566: see below
Strain, strain
background
(C. elegans)
lin-28(n719) I;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V;
fsEx567[Peat-4prom11::lin-28::
Sl2::mCherry::unc-54 3'
UTR + Pmyo-3::mCherry Line 2]
this paperUR1276n719: MT1524;
fsIs5: UR218;
e1490: UR218;
fsEx567: see below
Strain, strain
background
(C. elegans)
pha-1(e2123) III;
lep-2(ok900) IV;
him-5(e1490) V;
fsEx295[ODR-10::GFP
fosmid + pBx1];
fsEx568[Pgpa-4del6::lep-
2::Sl2::mCherry::unc-54 3'
UTR + Pelt-2::GFP Line 1]
this paperUR1277pha-1: GE24;
ok900: RB986;
e1490: UR926; fsEx295:
UR773; fsEx568:
see below
Strain, strain
background
(C. elegans)
pha-1(e2123) III;
lep-2(ok900) IV;
him-5(e1490) V;
fsEx295[ODR-10::GFP
fosmid + pBx1]; fsEx569[Pgpa-4del6
::lep-2::Sl2::mCherry::unc-54 3'
UTR + Pelt-2::GFP Line 2]
this paperUR1278e2123: GE24; ok900:
RB986; e1490: UR926;
fsEx295: UR773; fsEx569:
see below
Strain, strain
background
(C. elegans)
lin-28(n719) I; lep-2(ok900)
IV; fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V
this paperUR1279n719: MT1524; ok900:
RB986; fsIs5: UR218;
e1490: UR218
Strain, strain
background
(C. elegans)
lin-28(n719) I;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V; lep-5(ny28) X
this paperUR1280n719: MT1524; fsIs5:
UR218; e1490: UR218;
ny28: UR1022
Strain, strain
background
(C. elegans)
lin-28(n719) I;
fsIs5[Psrj-54::YFP + cc::GFP]
him-5(e1490) V; let-7(n2853) X
this paperUR1281n719: MT1524; fsIs5:
UR218; e1490: UR218;
n2853: MT7626
Recombinant
DNA reagent
MKRN3 (NM_005664)
Human Untagged Clone
OrigeneCat# SC319872
Recombinant
DNA reagent
pDONR221Invitrogenhttps://www.addgene.org/vector-database/2394/
Recombinant
DNA reagent
Peat-4prom11::lep-
2::SL2::mCherry::unc-54
3´UTR
this paperConstruction
described below
Recombinant
DNA reagent
Peat-4prom11::lin-
28::SL2::mCherry::unc-54
3´UTR
this paperConstruction
described below
Recombinant
DNA reagent
Pgpa-4del6::lep-2::SL2:
:mCherry::unc-54 3´UTR
this paperConstruction
described below
Recombinant
DNA reagent
Prab-3::MKRN3::SL2::
mCherry::unc-54 3´UTR
this paperConstruction
described below
Software,
algorithm
Prism 8GraphPad SoftwareRRID:SCR_002798
Software,
algorithm
ApE, A Plasmid EditorM Wayne DavisRRID:SCR_014266
http://jorgensen.biology.utah.edu/wayned/ape/

Data availability

Data is available in supporting files.

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